Lloyd was educated at Columbia College and admitted to the bar in 1869. After reform activity in New York City, in 1872 he joined the staff of the Chicago Tribune, where he worked for 13 years at the literary, financial, and editorial desks. “The Story of a Great Monopoly,” his documented study of methods used by the Standard Oil Company and the railroads to eliminate competitors, had a sensational effect when it appeared in The Atlantic Monthly (March 1881). It alerted the public to the need for antitrust legislation and served as a model for the new genre of muckraking journalism. His attack on monopolies was later expanded into his most important book, Wealth Against Commonwealth (1894).

After 1885 Lloyd devoted full time to public affairs as a supporter of free trade and of the rights of labour and of the consumer. In the 1890s he visited Europe and New Zealand to study social experiments, chiefly in the area of the reconciliation of industrial conflicts. Defeated in 1894 as a congressional candidate of the independent National People’s Party, he withdrew from active politics but supported the Socialists.